1. Field of the Invention
The present invention relates to a finisher, and more particularly to a finisher which distributes sheets ejected from a copying machine, a printer or the like.
2. Description of Related Art
Generally, an image forming apparatus such as an electrophotographic copying machine and a laser printer is provided with a finisher which distributes image-formed sheets into a plurality of bins while sorting the sheets and staples the sorted sets of sheets. In such a finisher, generally, stapled sets of sheets are kept on the bins, and the operator must take the sets of sheets out of the bins manually. Therefore, it is impossible to continuously make a larger number of copy sets than the number of bins.
In order to solve this problem, Japanese Patent Laid Open Publication No. 4-156391 has suggested a finisher which automatically takes stapled sets of sheets out of bins and stacks these sets of sheets in a stack section located in a lower part.
In such a finisher with an automatic stapled set take-out device, a bin and a set of sheets in the bin are moved to the rear side of the bin (first movement) for stapling of the set of sheets, and then, the stapled set of sheets is moved (second movement) in a direction perpendicular to the direction of the first movement for take-out of the set of sheets. Thus, in the finisher, a set of sheets is moved in two directions, and separate driving sources are necessary for the movements, thereby increasing the size and the cost of the apparatus.
It is also known that a chucking member is used for the movements of a set of sheets. In this case, the chucking member must be moved in the following manner: first, the chucking member is set in a first position to retreat from a bin and is moved to a second position to pinch a set of sheets in the bin and further moved to a third position to have the set of sheets protrude from the bin for stapling. In an existing finisher, for the two-step motion of the chucking member, separate driving sources, for example, a motor and a solenoid are provided. However, this increases the size and the cost of the apparatus.
On the other hand, each bin is provided with a stopper for regulating edges of sheets, and in order to pull a set of sheets out of the bin, the stopper must be moved from its regulating position. In an existing finisher, for the movement of the stopper, a driving source such as a motor is provided for exclusive use, thereby increasing the cost of the apparatus.